High-speed grinding spindle



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z/ f7 MNVENTOR.

ATTU RN EYS Oct. 9, 1945. J; c. STAFFORD HIGH `sPEED GRINDING SPINDLEFiled Jan. 5, 1943 therefrom.

OFFICE Jeanoysfaffora;Dayton-011i,

' v Application January 5, 1943, SeralNo. 471,337 y l 2 claims. (chaos-76) the like, and hasam'ong `its objects andf advantages the provisionof Aar-1vl improved high- "speed grindingspindle'.A 1 i I- Y -v- In'theaccompanying`dravvirigjA ,Y n' "Figure 1' isalongitudinallsectio'nalview-ofthe spindle with the' centralshaftthereof illustratedy inielevation. 'A f f r.li'gure 2 is an end View of a portier-1^ ofthespindle structure.'q

f A`Figurenv is `a sectionall View of al modified construction.

' InV the embodiment of the invention selected for illustration, I makeuse 'of a spindle'shaft I0 @shapedwitlr progressively'- smaller'diameter |4 andI-I. Upon the'diameter |14 o''theshaftf `isi mounted karoller bearing f I8, which `beam-ing "includesi'a race 2|! mounted on?the diameter Y|34 Vvbut-spaced. from the shoulder 2I.A The innerrace n28of the bearing 24 ts onZ thediam'eter `I26,F A

bushing "30T is interpo'se'dsbetween theA bearings ingsv I8. andl24,respectively. f

A tubularhousing 36' enclosesf the'VI tvifof roller lbearings and the.bushing 30;.1the` latterL having A:au sliding fit' in `the housing; A"bearing?.jam'- nut 38 is threadedly connected at 48 with-inne end ofthe` housing '3 andis providedv with abrass lip bushing I2` havingE` apush' fit "withfre'spectto the jamv nut. This, jam nutengagesftl'iefoutr `end of the bearing race'32. Between'th'e innerbearing-race 20` and the shoulder22i ist clamped a centrifugal dustguard land greasef lretain This guard. and retainer includesathin'wa 48bored to receive the diameter |4'r and provided with a flange 48'defining anannular. recess 58 housing the flanged end of theplip bushing4-2.`

A cap 60 is threaded'ly connectedat lrwith the 'front or that end of thehousing 36 facing the grinding wheel, not shown; Air ports 62'extendlongitudinally through the wall: of lthe housing 36 and havecommunication with annular recesses` B4 in the front capr 60 and theadjacent A Slightly My* invention relates to YrotaryI grinders-'and`Eigure 3 is a face view of an Va-ir circulating "fan, and` i v|8and2,4-ian'd. has: its ends re's'pectively-engag" Aing the outer races'32iand 34"ofthe"rollerbearpropeller fan 'III having a'push t on the shaftI0.

YA dust cap 'I2V also has a push fit fon the shaft |IJ and spaced fromthe end and outer peripheral face of the flange S3 for=the passage ofair circula-ted through the ports 62 and 66.

The outer bearing race 34 of the bearing 24 is clampedl againstthe'adjacent end of the bushing 30- by-a jam nut 14 threadedlyconnectedv at 16 With the housing 36.v A thrust bushing 18 has alsliding fit on the diameter I5. A brass lip bushing 8 0 has a slidingVfit onvthe thrust bushingf18 but a push fit in the jam nut 14. y n

Between thei'nner bearing race 28 and' the thrust bushing 18 isinterposed a centrifugalv dust guard'and grease retainer 82 having asliding fit on the shaft |0.""This guard and retainerv includes ay thinwall 84 clamped? between the Vthrust bushing 18 and the bearing race 28,which `Wall carries an annular flange 86 defining an annular recess 88loosely housing the flanged end of' the lip bushing'll. The flange 86includes an outer' face 9|) tapering away from the Wall 8'4.

yA slightly concaved flange v92 is carriedv by the wall'8'4 and divergesin the direction of the bearvi'n'g'rollers 94 butspaced therefrom. f

the, guardI and retainer 821 tapers outwardly from the'bearing'24.'r

A second housing cap 96 is threadedly connecte'd at 98 with the rear orthat end of the housing 36 facing the pulley |04, This cap and ltheadjacent end of the-housing 38 are provided With annular recesses I III)defining an annular port having communication with the atmospherethrough the medium of openings I 02 inthe housing a 'cavity |86 toprovide accommodation for -the cap'S-lf The pulley isspaced from the cap95. and includes a sleeve |88 cooperating with the I'I'Il havingasliding t on the shaft I0. The col- This wall` includes an annularflange I I4 arranged -coaxi'ally with the shaft I' and' provided with aninturned flange I6i spaced' from the wall I I2 and from the sleeve part`I I8 of the cap 86.

end of the housing 38 coacting'to'provide Van annular' port havingcommunication with. ports 66y in the cap 60 and converging axiallyY of,vthe yshaft I0. The outer endof thefcapv isvprovided with an annularflange 68 arranged: coaxially of the shaftA I0 and constituting ahousing for a A lock nut. |20 is threadedly connected with the -sliaft`I0 at |.22 and abuts the pulley |84 so that the latter may be adjustedto xedly relate the My invention incorporates roller bearings and i isso designed that play and end thrust may be eliminated to the end thatthe grinding spindle' may be employed in position work. `The Vmajordiiculty in connection with position bearings,

particularly of the ball type, resides in the rapidl.

wearing action of abrasive dirt and grit. A small particle of foreignmaterial, when introduced into a ball race may destroy the bearing in afew seconds of time. Such grit also includes magnetized steel grindingsthat adhere to any magneticmaterial in their vicinity. Y

voir. The opposite sides of the rotating members 44 and 82 consist ofcircular roofs or eaves, overhanging lipped bushings which surround thespindleshaft at these points and are fixedly related to the bearingconning jam nuts 38 and 14. The two members capture any drippings of oilthat might adhere to the parts when the device is not in motion, andconvey the accumulation to a point in theV vassembly away from anyopening around the spindle shaft through which it might otherwise escapeto the outside atmosphere, redepositing the oil in the bearings and theoil reser- 'Ihe atmosphere constitutes a vehicle for the y transmissionof dirt and grit. The atmosphere in the presence of grinding and wheeltruing operations is loaded with such minute particles, which can and doenter into the small clearance spaces between the rotating spindle shaftand its component parts. To overcome these diculties, my

invention operates to cause a current of air to flow outwardlyfrom'within the spindle assembly at the spindle nose where dirtordinarily enters. This current of air is supplied through the ports inthe end caps and the housing surrounding the Spindle shaft; butseparated entirely from the bearing chamber. This current of air isproduced by the fan 10 which is attached to the spindle shaft androtates therewith at spindle shaft speed.

The pulley |04 is located close to the rear dust cover 96, so thatcentrifugal forces at this point tend to catch and throw `any dust thatmight assemble thereabout. Should any magnetized particles adhere to thedevice through magnetism, or should grit tend to enter when the deviceis not in use or in' storage, such particles are preventedfrom enteringthe bearings by reason of the centrifugal collector ||0.

In connection with lubrication, a large part of the dirt and dust thatordinarily gives trouble in high speed bearings is deposited in thebearing oil stream by the oiler from the spout of the oil can. Mostspindles now in use are lubricated in this manner, and when light oil isused, it must be frequently replaced.

Sealed lubricant retaining bearings make use of lpackings, which areobjectionable sources of undesirable friction at high speeds. In theinstant case, oil seals of this type are eliminated. All ts are free,there being a definite space between -the spindle shaft and itssurrounding components. Nothing is theoretically a metallic contact withthe spindle shaft except the inner ball races, which are push fitted tothe shaft, and the end thrust adjustment is applied through the mediumpfthe cone pulley |04 threaded to the spindle shaft and anchored by thelock nut |20.

Ordinarily, in such loose tting assemblies, lubricant would quicklyescape. To prevent such escape, centrifugal forces are utilized throughthe instrumentalities of the guards and retainers 44 and 82, whichconstitute rotating baille means revolving at the same rate of speed asthe spindle shaft I0. These two members are soy shaped that i eachincludes an angular and circular lip on one side which extends into andhangs over the ball elements within its respective roller bearing. Thisconstruction continually collects lubricant attempting to escape,throwing it back into the bearings and then returning it to the oilreservoir when the device is again set in motion.

Grease is preferably employed in contradistinction to free flowing oil.Lubrication begins, when using the device rst through grease adhering tothe bearings when last used, and secondly the lubrication ilow iscontinued when a slight degree of frictional heat is attained whichsoftens and liquees the grease to va point where ample lubrication ismaintained at all times. The members 44 and 82 prevent the escape oflubricant and continually redeposits the lubricant within the ballraces, where it is required.

Y Both the collector ||0 and the dust guards and grease retainers 44 and82 are of brass, or other non-magnetic metal, so that charged particlesof steel grinding will not adhere thereto. `At the front end of thespindle where the most dust tends to accumulate and enter a device ofthis nature, a column of air blows outwardly to prevent the entrance ofdirt and grit at this point.

In Figure 4, the cap |24 and the bushing |26 are so shaped anddimensioned as to provide. an air cavity |28 completely sealed from thespindle length I2, since the bushing is closely tted in an annularrecess |30 in the cap |24.` Openings |32 Yare bored in the cap |24 toplace the cavity |28 in communication with the fan housingV |34, withthe air passages 62 in the housing 36 communicating with the air cavityor chamber |28.

Without fur-ther elaboration, the foregoing will so fully explain myinvention, that others may,

by applying current knowledge, readily adapt the same for use undervarious conditions of service.

I claim:

l. In a high speed grinder, a stationary tubular housing, caps on thefront and rear'ends of the housing, a spindle extending axially throughthe housing and caps, the spindle being adapted to carry a grindingwheel on its front end, a pulley on the rear end of the spindle, axiallyspaced front and rear bearing units within'the housing for rotatablysupporting the spindle, a dirt collector surrounding the spindle withinthe rear cap, a fan housing carried by the front cap in surroundingrelation to the front end of the spindle, the fan housing being providedat its rear side with air intake means and at its front side With airdischarge means, the spindle housing being provided with longitudinalpassages opening to the atmosphere at the rearend of the spindle housingand communicating at their front ends with the air intake means of thefan housing, and fan blades carried by the spindle for rotation therebyto cause air to flow through said passages to and through the fanhousing at the front end of the spindle.

2. A high speed grinder such as claimed in claim l, additionallycomprising a, dust cap mounted on the front end of the spindle andhaving an annular wall arranged in spaced surrounding relation to thecorresponding wall of the fan housing. y

JEAN C. STAFFORD.

